Vulcanized composition formed from sulfur, rubber, and an alkenyl phenol for joining metal, wood, glass, and thermosetting resins



Patented Dec. 15, 1953 VULCANIZED COMPOSITION FORMED FROM SULFUR, RUBBER, AND AN ALKENYL PHENOL FOR JOINING METAL, WOOD, GLASS, AND THERMOSETTING RESINS Herman S. Bloch, Chicago, Ill., assignor to Universal Oil Products Company, Chicago, 111., a

corporation of Delaware No Drawing. Application August 2, 1951,

Serial No. 240,034

6 Claims. (01. 260-455) This application is a continuation-in-part of my copending application Serial Number 673,482 filed May 31, 1946, now abandoned.

Thi invention relates to a bonding composition suitable for joining metal, wood, glass, and a thermosetting resin to each other or for joining pieces of one of these materials.

An object of this invention is to form a vulcanizable bonding composition by interacting unsaturated compounds and aromatic compounds.

Another object of this invention is to form a bonding composition by vulcanizing a mixture comprising a copolymer of butadiene and styrene and a resinous material formed by interacting butadiene and a phenol in the presence of an acid catalyst.

One embodiment of this invention relates to a bonding composition formed by vulcanizing a composite of sulfur, an unsaturated elastomer selected from the group consisting of natural rubber and a rubbery copolymer of butadiene and styrene, and a condensation product formed by interacting a conjugated diolefin and a phenol in the presence of an acid catalyst.

Another embodiment of this invention relates to a bonding composition formed by vulcanizing a composite of sulfur, a-rubbery butadiene-styrene copolymer, and an alkenyl phenol, said alkenyl phenol being formed by condensing a phenol and a conjugated diolefin in the presence of an acid catalyst.

A further embodiment of this invention relates to a bonding composition formed by vulcanizing a composite of sulfur, a rubbery butadiene-styren copolymer, and a resinous product formed by condensing a phenol and a conjugated diolefin in the presence of a phosphoric acid catalyst.

A still further embodiment of this invention relates to a bonding composition formed by vulcanizing a composite of sulfur, a butenyl phenol, and a rubbery butadiene-styrene copolymer.

A bonding composition suitable for joining concrete, stone, wood, metals, etc., with glass, tile, thermosetting resins, plastics, etc., comprises a vulcanizable material made by reacting a polyenic material such as a dienic or polyenic hydrocarbon or derivative thereof, such as butadiene, isoprene, chloroprene, piperylene, cyclopentadiene, etc., and a substituted aromatic compound selected from the class consisting of a phenol and aniline, a halogenated aromatic hydrocarbon and a thiophenol. These reaction products include such materials as (a) alkenyl phenols or ringsubstituted alkenyl phenols, for example, butenyl phenol or tertiary-butyl butenyl phenol; (12) alkenyl anilines, for example, butenyl aniline; (c) alkenyl thiophenols, or (d) alkenyl haloaromatics, for example, butenyl-mono-chlorobenzenes.

Thes materials may be represented by the formula AIRnHmXp, where Ar is an aryl nucleus, R is an alkenyl substituent, n is 1 or m is an integer at least equal to 3, p is 1 or 2, but the sum ofn plus 10 does, not exceed 3, and the X groups are separately chosen from the group comprising the halogen, hydroxy, amino, and thiol radicals.

The reaction products include also the condensation products of the materials (a), (b), (0) and (d) with aldehydes or ketones, for example, with formaldehyde; the products produced by the polymerization of the materials, (a), (b), (c), and .(d) and the high-molecular polymeric and condensation products formed as a resinous bottoms by-product in the preparation of the materials (a), (b), (c), and (d).

The preparation of successful bonding materials applicable to the bonding of the materials of Widely dissimilar characteristics, discussed above, involves consideration of the following principles: (1) the bonding agent should be capable of setting at a relatively low temperature, so as not to destroy materials which, like wood, are relatively heat-unstable; (2) the agent should contain ingredients capable of establishing firm bonds with polar materials such as wood or glass; (3) it should contain ingredients capable of establishing firm bonds with metals; (4) ingredient (2) should be the same as that of (3) or be capable of forming a stable compound with it.

Alkenyl phenols and other related condensation products of a phenol and a conjugated diolefin which may be used as a starting material in this process may be obtained by reacting one molecular proportion of a, conjugated diolefin with from about 0.25 to about 5 molecular proportions oi'a phenol in the presence of an acid catalyst at condensation conditions. Suitable acid catalysts include a phosphoric acid, a composite of a phosphoric acid and an ether, a composite of a phosphoric acid and a siliceous adsorbent precalcined at a temperature of from about 250 to about 600 C., an acid-acting metal phosphate, and the like. The phosphoric acid containing catalysts are so employed at a temperature of from about 25 to about 300 C. and at a pressure of from substantially atmospheric to atmospheres or more.

Condensation of a conjugated diolefin with a acid catalyst or acid phosphate catalyst main;- 1

tained at a temperature offromabout Z? to about 300 C. and preferablyjat, a .teir'iperaturfe'of from about 75 to about 250f 1C. "The reactio'nfis also carried out at a pressureifi foinfs'ubs antia lly j f atmospheric to about 150 atmospheres at 'more,

the pressure generally being" sufficient to main-' tain a substantial proportion of thereaotarits'i'ri" liquid phase.

The step of condensing a phenolwithadiolefin may also be carried out in a batch type opera tion by adding the diolefin continuously to a stirred mixture of the phenol and a alyst, such as orthophos phoric acid or a complex of a concentrated phosphoric a'ci'c'i'and'an' ether; such as a complex of 100% orthophosphoric acid-and substantially anhydrous'd'iet'hyl ether.

The products sojformed' by'reacting a conjugated diolefin and a phenol in the presence'of a phosphoric acid cataylst'are separated into a catalyst layer and an organic product layer, the latter being then separated into unconverted phenol and reaction products. The" reaction products may be fractionally distilled to separate lower boiling products from higher boiling residue or they may be 'subj'ected'to extraction with a caustic sodasolution in order to dissolve phenolic materials in the caustic soda solution and thereby separate phenolic reaction products from certain substantiallyheutral condensation products, such asethers, resins; etc; 'The condensation reaction product, which is soluble in caustic soda solution is then recovered as'an oily layer .by neutralizing thecaustlc' soda solution with an acid or by reacting thecausti'csoda solution with carbon dioxide so astoliberate dissolved phenols" such as the alkenybphenolsto gether with some unconverted phenolic starting material. The .mixtiire of phenols and alkenyl phenols. so obtainedis then'subjected to fractional distillation in order to separate unconverted starting material; monoalkenyl. phenols such as butenyl phenols or'pentenyl phenols, and higher boiling condensation products.

In the case of bonding'compositions formed by vulcanizing composites containing "butenyl phenols or the resinous residues formedii'n the preparation of butenyl phenols by the alkylation of phenol with butadiene in the presence of phosphoric acid, the presence of residual unsaturation permits vulcanization of the material with sulfur at temperatures of from about 125 to about 200 C. This vulcanization treatment is carriedout fora time of from about 0.5 toiabout 10 hours; Thephenol groups are capable of firm .attachment to polar materials-for example,1by hydrogen bonding with the oxygen of the hydroxy groups of cellulosic materials or with the oxygen in glass. The unsaturated linkages are capable of forming firm bonds with metalsprobably by way of the sulfur used in vulcanization. Finally, if the butenyl phenol derivative or other alkenyl phenol derivative .isused alone, condition (4) above is met, or if it is used in. conjunction with some other vulcanizable material, for example, rubber, which bonds to metals via sulfur, the butenyl phenol compounds are capable. of linking with the rubber by copolymerizationyby coliqunrcat 4 vulcanization, or by the formation of chroman rings.

The alkenyl phenols, alkenyl thiophenols, alkenyl haloaromatics, or alkenyl anilines, or their polmers, or their aldehyde condensation products, with sulfurand the conventionally used accelerators and other additives such as carbon black, zinc oxide, and the like, may be used with or Without vulcanizable elastomeric material containin'gidoublebonds, such as a natural or synthetic rubber, for example, butadiene-styrene copolymer; to form a heat-curable all-purpose bondingagnt'; Since, in the milling of these materials with rubber; the material may stick to the rolls, it may be desirable also to incorporate additi'onal plasticizers or solvents in such compositions. If natural or synthetic rubber comprises partg'f the'bonding, the diene-phenol condensation product (or an analogue thereof, as described above) may be used in an amount comprising from about 5 to about 50% of the bonding composition; generally from about 10% to about 25% is most satisfactory.

The following examples are given to illustrate the type of bonding composition referred to above,' although the data present are not includedwith the intention of restricting unduly the broad scope of the invention.

EXAMPLE I 0 Z5 Grams Percent Unractcd phenol 180-192 676 I 35.0 Mixture of unrcactcd phenol and 192*200 319 10.5

butenylphcnoL v Butenylphonoliraction 20028l 304 15.8 Rcsinous bottoms Over 281.." 535 27.8

Unaccounte'd loss The'butenyl phenol'fraction was colorless and had a pleasant odor. The residue was a hard; brittle dark brown-red mass.

parts by weight of a rubbery butadienestyre'n'e'copolymer (GR-8) 50'parts by weight of carbon black (Kosmobile l'l) 20 parts by weight of the resinous bottoms formed from butadiene and'ph'enol and' boiling above28l C., 5 parts by weight of zinc oxide; '3 parts by weight of sulfur, and'l'.5 parts by'weight of 2-mercaptoben'zothiazole'were mixed ona rubber mill to form-a homogeneous rubber-like mass; The resin incorporated in'this milled material was a dark brittle substance obtained as'the distillation residue in the experiment described above.

The material mixed on the rubber mill as above indicated was thenvuloanized between two overlappingpieces of'soft steel (0.8 mm; thick) at a temperature 'of' C. and' under a pressure of"1000 p. s. i. for'50 minutes. The vulcanized material-formed a firm'bond to the steel, thus firmly bonding together the two steel strips used in the'test;

A phosphoric acid-ether complex was'formed by adding anhydrous ether through a dropping funnel at room temperature to 85% orthophos- Dhoric acid contained in a 5 liter round bottom glass vessel equipped with a 1-liter dropping funnel, a mercury sealed stirrer, thermometer, a reflux condenser cooled by solid carbon dioxide and on the outlet of which was a calcium chloride drying tube. The phenol was then added and the flask and contents cooled to around C. Isoprene, which had previously been redistilled, was then added through the dropping funnel over a one-half hour period while keeping the temperature at about C. by cooling with ice. The product was then stirred for an additional 1.5 hours while maintaining a temperature of 25 C. After a short settling time the lower acid layer was separated, the upper product layer transferred to a 2 gal. glass bottle and washed twice with 1000 cc. of distilled water, once with 1000 cc. of 5% NaHCOa solution and then twice with 1000 cc. of distilled water.

The accumulated product from three runs was then distilled through an 8 foot jacket heated glass column having a 2 inch inside diameter and packed with 0.25 inch glass helices. After bringing overhead the ether and water at atmospheric pressure, the unreacted phenol and higher boiling product were distilled at a reduced pressure of about 4 mm.

Selected fractions, as determined by n measurements were then treated in a 5 gal. glass bottle with 1% times the theoretically required amount of 20% NaOH solution and the solution diluted with about twice its Volume of distilled water and extracted twice with n-pentane. The pentane extract was treated with a small amount of 20% NaOH solution which was then diluted with water, separated and added to the main bulk of caustic solution. The pentane extract was then dried with anhydrous Na2SO4 and the pentane distilled ofi to recover neutral compounds.

The caustic solution was acidified with solid CO2, n-pentane added and the upper layer separated. The water was again extracted with npentane, the two pentane extracts combined, water washed, dried over anhydrous NaaSO-r and the pentane distilled off to recover the caustic soluble pentenyl phenols. The combined products were then distilled through the 8 foot fractionating column mentioned above to recover pure pentenyl phenol. In these runs 64% of the phenol was recovered unchanged while the pentenyl phenol fraction amounted to 38.4% of the isoprene charged.

This pentenyl phenol fraction was employed in the following formulation, which was milled as described in Example I:

Parts GR-S Kosmobile-77 50 Pentenyl phenol 20 Sulfur 4 Zinc oxide 5 2-Mercaptobenzothiazole 1.5

The milled composite formed an excellent bond between sheet aluminum and steel plate when a sandwich of the bonding agent was vulcanized between the two metals for 1 hour at C. and 750 p. s. i. pressure.

I claim as my invention:

1. A bonding composition comprising sulfur, an unsaturated elastomer selected from the group consisting of natural rubber and a rubbery copolymer of butadiene and styrene, and a condensation product of phenol with a conjugated diolefin hydrocarbon selected from the group consisting of butadiene and isoprene.

2. A bonding composition comprising sulfur, an unsaturated elastomer selected from the group consisting of natural rubber and a rubbery copolymer of butadiene and styrene, and an alkenyl phenol condensation product of phenol with a conjugated diolefin hydrocarbon selected from the group consisting of butadiene and isoprene.

3. A bonding composition comprising sulfur, an unsaturated elastomer selected from the group consisting of natural rubber and a rubbery copolymer of butadiene and styrene, and a resinous condensation product of phenol with a conjugated diolefin hydrocarbon selected from the group consisting of butadiene and isoprene.

4. A bonding composition comprising sulfur, a rubbery copolymer of butadiene and styrene, and a condensation product of from about 0.25 to about 5 molecular proportions of phenol with 1 molecular proportion of a conjugated diolefin hydrocarbon selected from the group consisting of butadiene and isoprene.

5. The composition of claim 4 further characterized in that said condensation product is an alkenyl phenol.

6. The composition of claim 4 further characterized in that said condensation product is a resin.

HERMAN S. BLQCH.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,819,416 Harvey Aug. 18, 1931 2,296,363 Messer Sept. 22, 1942 2,320,746 Paul June 1, 1943 2,337,464 Hecht Dec. 21, 1943 2,353,282 Turkington July 11, 1944 

1. A BONDING COMPOSITION COMPRISING SULFUR, AN UNSATURATED ELASTOMER SELECTED FROM THE GROUP CONSISTING OF NATURAL RUBBER AND A RUBBERY COPOLYMER OF BUTADIENE AND STYRENE, AND A CONDENSATION PRODUCT OF PHENOL WITH A CONJUGATED DIOLEFIN HYDROCARBON SELECTED FROM THE GROUP CONSISTING OF BUTADIENE AND ISOPRENE. 